Studies on the diagnosis of foreign bacterial diseases of quarantine significance VII. preparation of selective medium and antiserum for the detection of Clavibacter michiganensis subsp. nebraskensis.

摘要

A selective medium (NSM) was developed for isolating Clavibacter michiganensis subsp. nebraskensis, the causal agent of Goss's wilt, which is seedborne and of no occurrence in Japan. Also, antiserum was prepared for diagnosis of it. On NSM, Cl. m. subsp. nebraskensis formed capitated, smooth and salmon-pink colonies after 3-4 days incubation at 30鳦, and blackening of the medium around the colonies was observed. Depending on this colony characteristic, Cl. m. subsp. nebraskensis was easily distinguished from other bacteria such as Cl. m. subsp. michiganensis, Curtobacterium flaccumfaciens pv. flaccumfaciens, Rhodococcus fascians etc., which could grow on NSM. The colony forming efficiency on NSM was 72-177%. In gel-double-diffusion test and slide-agglutination test using the antiserum against this bacterium and various antigen of the other bacteria, it suggested that there was a relatively antigenic homogeneity among all 13 strains of Cl. m. subsp. nebraskensis. The antiserum absorbed with the antigen of Cu. fl. pv. flaccumfaciens, which had a weak reaction with crude antiserum, had become more specific on subspecies level. Therefore, NSM and the antiserum are useful for diagnosis of the disease caused by Cl. m. subsp. nebraskensis.